Nagai Type of Japanese Iris
Hiroshi Shimizu @@@

The Nagai type of Japanese iris is older than the other three types, i.e. Edo, Ise, and  Higo. Last year I visited the city of Nagai in Yamagata Prefecture for the first time. My purpose was to investigate the Nagai varieties. The Nagai district is a very important place for Japanese iris lovers, especially for those who are interested in the origin of garden cultivars. That is because the Nagai type is very old and cultivated only in the Nagai district.
 Mr. Toshihiro Nagata, who grows Japanese irises for Kamo nursery, and I visited   Nagai city in June ,1997. Nagai is located in northwestern Honshu. We went by train and at Nagai station by Mr.Kakima, who is a key person for our planned investigation. Mr.Kakima is an enthusiast of Nagai varieties and has tended them as a volunteer at   Nagai Ayame Garden for a long time.

Nagai Ayame Garden
We first went by car to Hagyu village on Nagai plain.  It is a quiet farming village where there are many rice paddy fields. Upon taking a short walk, we found many flowers of wild Iris ensata growing along the dikes of rice field. These irises were not cultivated forms that had been naturalized, but truly wild plants. This was evident by their simple flower form with three narrow falls and almost no color variation. 
 After resting, we followed Mr.Kakima to a stream on a hill near the border of the   Ide-mountain range and the Nagai plain. We found many flowers of the wild species in bloom in a meadow on the hill. We felt fortunately to find two plants of the pink form of the species. Mr.Nagata and I were excited at this finding but Mr.Kakima remained calm.  He told us that there are many mutants forms of the wild species in the meadows of the Ide mountains. I concluded that this particular meadow and the dikes of the rice paddies must be secondary habitats of the wild species. The meadows near the top of the mountains must be the primary habitat of the wild irises. Perhaps using this area for agriculture expanded the habitats. Nagai district has rich soil and a diversity of native flora, bird, animals and insects. Here many natural variants of iris ensata have survived. The people who live in northern Honshu, and especially in Nagai district, protect nature. So wild species have great potential for developing cultivars in the future.
wild ensata growing along riice paddies Pin form of ensata

  We visited Nagai Ayame Garden next day. This garden has cultivars of Ise, Higo, Edo, American and Nagai types of Japanese4 irises. We concentrated on the Nagai varieties. I made a number of observations about these irises:
1. About half of the cultivars had simple forms with narrow falls and standards, but they showed a very wide range of color and pattern variations.
2. The other half of the cultivars had color and patterns similar to old Edo cultivars, but flower shapes and sizes were intermediate between the wild species and the  old Edo varieties.
3. Some of the Nagai cultivars had flowers with a form different form any other type.

The old records of this garden reveal that it was established in 1919, by collecting Japanese iris plants from many private gardens in Nagai and Hagyu villages. These varied widely in colors and patterns. Mr.Kakima explained that Hagyu villagers had collected many mutant forms from the nearby mountains and plains for their gardens. They enjoyed the blooms, and often drank sake while viewing them. The bloom season coincided with the time when villagers took a vacation from their agricultural work.
Hagyu village was a castle town in the olden times, and very crowded. It had long been the home of cultured people who enjoyed collecting, growing and appreciating clones of Iris ensata. I believe that the following factors were necessary for this "birth":

1.  Gene pool:  Many mutants were brought into a limited area from the wild.
2.  Open pollination by bees: The resultant seeds increased the flower's variation.
3.  Devotees:  Many people enjoyed the flowers, selected the most beautiful forms, and possibly they exchanged the best flowers.                    

 The iris breeding activity of Japanese gardeners has always differed from that practiced in the West. European gardeners obtain new cultivars by crossing different species, but Japanese gardener pursues variation by gathering mutants from the countryside.
 As an aside, I believe that the addition to the gene pool of with forms was probably critical to development of a wide variety of colors in cultivars of Iris ensata. The wide range of color and patterns would not be possible without genes for the white color.
If there were not a pool of recessive genes for white, other mutant color variations would be masked with purple or violet, which are the dominant genes in the species.
 There is no sign of any species other than Iris ensata having played a role in the development of the Japanese irises. All cultivars and wild forms of Japanese iris have the same chromosome count (2n=24). The only exceptions are aneuploid of Ise variety (2n=25), and these cross readily with natural diploids. Therefore they are regarded botanically as belonging to the same single species. The Nagai type is the oldest of all the Japanese iris groups which survived today. Its existence gives us hints as to how the modern cultivar was born, and provides material for future hybridizing.


Nagai type of Jananese Iris photo page 1/photo page 2